Watts to Kilowatt-Hours (kWh) Electrical Conversion Calculator
Convert watts to kilowatt-hours by entering power in watts and time in hours.
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How to Convert Watts to Kilowatt-Hours
A kilowatt-hour, expressed as kWh, is a measure of energy that is equivalent to 1,000 watts of power for a 1 hour time period. Thus, to convert watts to kilowatt-hours, multiply the power in watts by the number of hours, then divide by 1,000.
Use the following formula to calculate kWh:
kWh = (watts × hrs) ÷ 1,000
For example: let’s find the kWh of 1,500 watts for 2.5 hours.
kWh = (1,500 × 2.5) ÷ 1,000
kWh = 3,750 ÷ 1,000
kWh = 3.75
Electricity usage is often measured in watt-hours or kilowatt-hours, so if you can convert watts to kWh then you can predict how much an electric appliance might cost, or how much energy is required to power it.
For example: let’s predict how much it costs to power a light bulb every hour. A 100 watt light bulb uses 100 watts of power. To convert the power in watts to kilowatt-hours, multiply 100 watts by 1 hour, then divide by 1,000 to find the energy usage in kWh.
Energy = (100 × 1) ÷ 1,000
Energy = 100 ÷ 1,000
Energy = 0.1 kWh
If electricity costs $0.12 per kWh, then a 100 watt light bulb will cost 1.2 cents per hour that it’s on.
Common Watts to Kilowatt-Hour Conversions
| Power in Watts | Energy in Kilowatt-hours | Electricity Cost |
|---|---|---|
| 100 W | 0.1 kWh | $0.012 per hr |
| 200 W | 0.2 kWh | $0.024 per hr |
| 300 W | 0.3 kWh | $0.036 per hr |
| 400 W | 0.4 kWh | $0.048 per hr |
| 500 W | 0.5 kWh | $0.060 per hr |
| 600 W | 0.6 kWh | $0.072 per hr |
| 700 W | 0.7 kWh | $0.084 per hr |
| 800 W | 0.8 kWh | $0.096 per hr |
| 900 W | 0.9 kWh | $0.108 per hr |
| 1000 W | 1 kWh | $0.112 per hr |
Need to convert to watts? Use our kWh to watts conversion calculator.
